CVE-2021-26956: Xcb Arbitrary Return Types Vulnerability
CRITICALCVE-2021-26956 is a CRITICAL (CVSS 9.8) arbitrary return types vulnerability (CWE-657: Violation of Secure Design Principles) affecting Xcb libraries in the crates.io ecosystem. The issue involves arbitrary return types in xcb. Remediation is available by upgrading affected packages to version 1.0.0.
CVE-2021-26956 at a Glance
Security Impact
CVSS: 9.8
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
How to Fix CVE-2021-26956
To remediate this vulnerability, upgrade all affected Xcb dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade xcb to 1.0.0Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for xcbHow to Check if You Are Affected
To determine whether your application is affected by CVE-2021-26956, inspect your project dependencies for Xcb:
inspect dependencies for xcbAnalyze the terminal output to locate any version of Xcb in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.0.0), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-657: Violation of Secure Design Principles, where the product violates well-established principles for secure design. In Xcb, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2021-26956 Affected Xcb Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
xcb
|
crates.io |
< 1.0.0
|
1.0.0
|
References
Frequently Asked Questions
What is CVE-2021-26956?
Which Xcb versions are affected?
What version fixes CVE-2021-26956?
Is xcb affected?
What is the CVSS score of CVE-2021-26956?
What CWE is associated with CVE-2021-26956?
How can I check crates.io dependencies for CVE-2021-26956?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-mp6r-fgw2-rxfx",
"modified" : "2023-06-13T22:28:51Z",
"published" : "2021-08-25T20:53:27Z",
"aliases" : [ "CVE-2021-26956" ],
"summary" : "Arbitrary return types in xcb",
"details" : "The function xcb::xproto::GetPropertyReply::value() returns a slice of type T where T is an unconstrained type parameter. The raw bytes received from the X11 server are interpreted as the requested type. The users of the xcb crate are advised to only call this function with the intended types. These are u8, u16, and u32.\n\nThis issue is tracked here: https://github.com/rust-x-bindings/rust-xcb/issues/95",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "crates.io",
"name" : "xcb"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "1.0.0"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-26956"
}, {
"type" : "WEB",
"url" : "https://github.com/RustSec/advisory-db/issues/653"
}, {
"type" : "WEB",
"url" : "https://github.com/rust-x-bindings/rust-xcb/issues/95"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/rtbo/rust-xcb"
}, {
"type" : "WEB",
"url" : "https://rustsec.org/advisories/RUSTSEC-2021-0019.html"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-657" ],
"severity" : "CRITICAL",
"github_reviewed" : true,
"github_reviewed_at" : "2021-08-19T17:35:46Z",
"nvd_published_at" : null
}
}